Organizations such as on-line retailers, Internet service providers, search providers, financial institutions, universities, and other computing-intensive organizations often conduct computer operations from large scale computing facilities. Such computing facilities house and accommodate a large amount of server, network, and computer equipment to process, store, and exchange data as needed to carry out an organization's operations. Typically, a computer room of a computing facility includes many server racks. Each server rack, in turn, includes many servers and associated computer equipment.
Because the computer room of a computing facility may contain a large number of servers, a large amount of electrical power may be required to operate the facility. In addition, the electrical power is distributed to a large number of locations spread throughout the computer room (e.g., many racks spaced from one another, and many servers in each rack). Usually, a facility receives a power feed at a relatively high voltage. This power feed is stepped down to a lower voltage (e.g., 110V). A network of cabling, bus bars, power connectors, and power distribution units, is used to deliver the power at the lower voltage to numerous specific components in the facility.
From time to time, elements in the power chain providing power to electrical systems fail or shut down. For example, if a power distribution unit that provides power to electrical systems is overloaded, an overload protection device in the power distribution unit (for example, a fuse or breaker) may trip, shutting down all of the electrical systems that are receiving power through that line of the power distribution unit.
In many rack system installations, the rack power distribution units include a strip or bank of numerous output receptacles (for example, 12 or more receptacles). The large number of receptacles is often useful if the rack holds a large number of individual servers, fans, and other powered equipment. At the same time, however, excess receptacles waste valuable rack space. In addition, the large number of receptacles in a rack power distribution unit may also increase the possibility for an overload of a rack power distribution unit, as maintenance personnel plug device after device into the empty output receptacles.
The risk of overload of a rack power distribution unit may be greater in cases where a rack holds a single large piece of equipment with a few large power supplies (for example, a switch system with four 6.0 kilowatt power supplies). Although the power supplies for the piece of equipment use only a few of the available output receptacles (for example, one receptacle per power supply), the power supplies for the piece of equipment may use up nearly all of the capacity of the rack power distribution unit.
While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and will herein be described in detail. It should be understood, however, that the drawings and detailed description thereto are not intended to limit the invention to the particular form disclosed, but on the contrary, the intention is to cover all modifications, equivalents and alternatives falling within the spirit and scope of the present invention as defined by the appended claims. The headings used herein are for organizational purposes only and are not meant to be used to limit the scope of the description or the claims. As used throughout this application, the word “may” is used in a permissive sense (i.e., meaning having the potential to), rather than the mandatory sense (i.e., meaning must). Similarly, the words “include,” “including,” and “includes” mean including, but not limited to.